A central challenge in Neuroscience is to understand how complex three-dimensional networks of neuronal cells form synapses and generate neuronal activity. Traditional neuronal cell culture requirements and electrophysiological techniques have limited in vitro studies of neuronal cells to the examination of relatively few cells interacting in only two dimensions. In order to study the principles of neuronal network formation in native neuronal tissue, in vitro methods must be developed to allow for high cell density and connectivity, while simultaneously enabling controlled gene expression and non-invasive techniques for examining and stimulating individual cells. Currently available biomaterials have failed to support neuronal cell branching in three dimensions at an appropriate scale.
Neuronal degeneration is at the origin of many neurological disorders. Since the mammalian central nervous system has a limited capacity for self-repair, tissue replacement has been explored as a treatment option for many neurological disorders. However, tissue replacement techniques have only found limited success because neuronal cells are highly differentiated and have delicate processes. Transplantation of neuronal cells typically results in a loss of the differentiated phenotype and/or damage to the neuronal cell processes. Transplantation of non-differentiated cells, such as stem cells, has had some limited success, but only a small fraction of the transplanted cells differentiate into the desired neuronal cell phenotype, and most fail to integrate into the surrounding native neuronal tissue.
The present invention addresses these needs.